# if 5>12:
#     print("5 is greater than 2")
#     print("22222")
# else:
#     print("5 is not greater than 2")
#
# age=30;
# if age<18:
#     print("You are underaged")
#     #&&不可用
# elif age>=18 and age<30:
#     print("You are young")
# elif age>=30 and age<50:
#     print("You are middle-aged")
# else:
#     print("You are old")
#
# #判断闰年
# year =int(input("请输入年份"))
# if (year%4==0 and year%100!=0) or (year%400==0):
#     print("%d是闰年" % year)
# else:
#     print("%d不是闰年" % year)


# #abc比大小
# a = int(input("请输入a:"))
# b = int(input("请输入b:"))
# c = int(input("请输入c:"))
# if a>b:
#     if a>c:
#         print("a is the largest")
#     else:
#         print("c is the largest")
# else:
#     if b>c:
#         print("b is the largest")
#     else:
#         print("c is the largest")


# 计算机实现加减乘除
num1=float(input("Enter first number: "))
num2=float(input("Enter second number:"))
op=input("Enter运算符：")
if op == "+":
    print(num1+num2)
elif op == "-":
    print(num1-num2)
elif op == "*":
    print(num1*num2)
elif op == "/":
    print(num1/num2)
else:
    print("输入错误")
